'^LIBRARY OF CONGRESS.^' 



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UNITED STATES OF AMEEICA. 



TABLES 



FOR THE USE OF STUDENTS AND BEGINNERS 



VEGETABLE HISTOLOGY. 



5^pvwxr 



BY 



D^PrPENH ALLOW, B.S., 

iATE FROFESSOR OF CHEMISTRY AXD BOTANY IN THE IMPERIAL COLLEGE 
OF AGRICULTURE, JAPAN. 



'-I' 




/l-C 6 1882/ 



BOSTON: ~' 

S. E. CASSIXO, PUBLISHER. 
1SS2. 



Copyright. 1882, 
By D. p. PENHAjlLOW, 



Boston Stereotype Foundkt, 
No. 4 Pearl Street. 






This little work being the first of the kind that has 
been issued, it has seemed desirable not to make it too 
extended until the plan has received more general 
approbation from those qualified to judge of its merits 
and defects. If, however, there is sufficient encourage- 
ment, it is proposed to issue a second edition, in which 
the plan will be much extended, thus making it of 
greater advantage to the beginner, and also useful to 
the advanced student. With this end in view, sugges- 
tions from teachers and practical histologists will be 
gladly welcomed. d. p. p. 



PREFACE 



This little book was first conceived as an aid 
to the author's own students in the study of 
vegetable histology. The entire lack of a work 
of this kind, and the desirability of giving stu- 
dents, particularly those who have to work 
largely by themselves, something which would 
meet a long felt want, seemed sufficient excuse 
for putting the facts here stated into suitable 
form for general distribution. The aim has been 
to so bring together the most prominent facts 
and reactions of an elementary course of his- 
tology, that the student may have them on his 
w^ork-table ready for immediate and constant 
reference, and use them as a general guide in 
pursuing his studies. To make them true work- 



VI PREFACE. 

ing-tables, blank leaves are supplied on which 
the student can make note of such important 
facts as come under his notice, but are not rpen- 
tioned here. Also, at the end will be found the 
outlines of a course for one just commencing 
histology. While making no pretensions to com- 
pleteness in the plan as presented, the author 
will feel amply repaid for his labor if this little 
manual serves to give a stimulus to the study of 
this particular branch of botany. 

D. P. P. 

Cambridge, Feb. 13, 1882. 



REAGENTS 

AND 

MEDIA FOR EXAMINATION, 



Water. — In this fluid we have, perhaps, the 
most convenient means for the accomplishment 
of general solutions, and as a medium for the 
examination of the great majority of vegetable 
substances it cannot be excelled. For the or- 
dinary examination of structure in general, good 
spring water may be used if there is no other 
obtainable; but it is far better for all purposes 
to use only that which has been distilled, or, this 
failing, rain water may be substituted. The im- 
portance of using distilled water will be obvious 
when we bear in mind that it is very necessary 
to exclude from our examinations every object 
in any way foreign to the one under special 
consideration ; and particularly is this true in 
making delicate chemical reactions, where min- 
eral salts in solution would be extremely liable 



8 REAGENTS AND MEDIA. 

to bring about some other reaction than the one 
we are looking for. In making sections, water 
is an important fluid for keeping the razor moist, 
that it may make good, clean cuts. The in- 
stances in which it cannot be used are but few, 
as when we are looking for aleurone, which is 
soluble in water. 

Oil. — Fixed oils are sometimes useful as 
media for the examination of such objects as 
would be soluble in water or other fluids, such 
as aleurone, etc. Any good, clean oil will 
answer, though sweet oil, being generally at 
hand, will be the most convenient. As other 
oils are soluble in it, it causes a clearing-up of 
oily tissues, thereby rendering the more solid 
cell-contents much more distinct. 

Glycerine. — While this fluid may with ad- 
vantage be used for the purposes just mentioned, 
it has a more extended application, either alone 
or with varying proportions of water. It is an 
important medium for the examination of al- 
eurone and crystalloids. In the same forms it 
is an excellent medium for the more perma- 
nent preservation of objects. Its antiseptic 



REAGENTS AND MEDIA. 9 

properties make it valuable in this direction, 
as well as its attraction for water. This latter 
property causes objects, when first immersed in 
it, to shrink somewhat, but, as the glycerine 
penetrates the structure and replaces the water 
more completely, the object regains its original 
volume. Being a highly refractive fluid, it has 
a strong tendency to make dense structures more 
transparent, hence, delicate cell tissues often be- 
come invisible, while the most dense are shown 
to better advantage. It is also important in 
the examination of objects by polarized light. 
Owing to its ready solubility in water, tissues 
once impregnated with it, and possibly swollen 
to abnormal dimensions, may be restored to 
their original form by simple immersion in 
water. Furthermore, objects which have been 
so treated are still suitable for other treatment. 
We can hardly attach too much importance to 
this fluid. 

Alcohol. — The first and most obvious value 
of this reagent is found in its strong afiinity for 
w^ater, this rendering it of importance for de- 
hydrating purposes. When brought in contact 



lO REAGENTS AND MEDIA. 

with substances containing water, they are re- 
duced in volume, and all such structural features 
as stratification and striation, which depend upon 
the presence of water in variable quantity, disap- 
pear. This action will of course be more marked 
in structures which contain the largest amount 
of water. Its affinity for water renders it of value 
for the permanent preservation of objects, and as 
immersion in water will restore most bodies to 
their original form, objects are conveniently pre- 
served m it for future examination. For this 
purpose, as well as for general use, the alcohol 
should be of ninety-five per cent strength. For 
some special purposes of dehydration, absolute 
alcohol is needed. It is an important solvent. 
Chlorophyll and other pigments are brought into 
solution by it, and the tissues so treated become 
transparent, or at least colorless. It also acts 
upon oils and resins to dissolve them. When 
tissues contain air, it may be removed by im- 
mersion in alcohol. 

Ether. — The value of this liquid lies in its 
power to dissolve chlorophyll, oils, resins, etc. 
It is therefore of use in cleaning: tissues for 



REAGENTS AND MEDIA. II 

mounting, or for the recognition of special cell- 
contents. 

Caustic Potash. — For this reagent we may 
substitute caustic soda, the reaction being the 
same in either case. It is of first importance as 
a solvent of all albuminous compounds; hence 
is useful m cleaning tissues for the display of the 
cell-wall, or of the more insoluble cell-contents, 
such as crystals, etc. For this purpose we must 
use diluted solutions, as strong alkali does not 
dissolve protoplasm. A solution of the strength 
used by druggists, of sp. gr. 1.065, will be found 
to answer for most purposes. The action of 
alkali upon starch and cellulose is to cause an 
imbibition of water, hence these structures swell 
up, and, as in the case of starch, lose all form 
and finally dissolve. Upon cell-walls the action 
is to develop stratification and striation. It is 
thus a valuable agent in the examination of 
cuticle and similar structures. Unless the ac- 
tion is too long continued, tissues thus treated 
may be restored to their original form and vol- 
ume by soaking in water or very dilute acetic 
acid. Delicate tissues must not be allowed to 



12 REAGENTS AND MEDIA. 

lie too long in potash, as it would dissolve them. 
It has a tendency to dissolve oils, especially 
v^hen hot, but for a removal of such substances 
it is far better to rely upon the action of ether. 
Upon resins it exerts a solvent action. Upon 
grape sugar it acts to decompose. 

Ammoniated Copper Oxide. — This solu- 
tion, w^hich should alv/ays be used as fresh as 
possible, is a very ready solvent of cellulose. 
The latter may be precipitated from its solution 
by acids, in a pure state. The solution should 
have a strong alkaline reaction, and may be pre- 
pared by digesting copper turnings or filings in 
strong ammonia until a solution of deep blue 
color is obtained. 

Acetic Acid. — An important reagent for the 
study of crystals. The oxalate of lime is insol- 
uble in it, w^hile the carbonate dissolves wnth 
effervescence. Acting upon albuminous sub- 
stances to coagulate them, it renders proto- 
plasmic bodies more conspicuous, and often 
enables us to recomiize nuclei w^hen otherwise 
they would not be distinguished from the other 
cell-contents. It renders cellular structure more 



REAGENTS AND MEDIA. 1 3 

transparent. The most convenient solution is 
composed of one part acid and four or five parts 
w^ater. 

Hydrochloric Acid. — Concentrated acid, 
diluted with three or four volumes of w^ater, is 
useful in dissolving crystals and other mineral 
substances. It acts upon starch to convert it 
into dextrine and grape sugar. It coagulates 
protoplasm and dissolves aleurone. 

Sulphuric Acid. — Strong acid, one part ; 
water, three or four parts. This dissolves min- 
eral substances and aleurone, and coagulates 
protoplasm. Upon starch, the effect is to dis- 
solve it with the formation of glucose. Upon 
the cell-wall the action is the same, though not 
so rapid, unless the acid is strong. It renders 
the iodine reaction possible in resisting struc- 
tures such as the cell-wall. 

Nitric Acid. — This should be kept on hand 
of two degrees of concentration ; viz., fuming 
acid diluted with an equal volume of water, and 
fuming acid diluted with four parts of water. 
Mineral substances are dissolved by it, and pro- 
tein compounds take a bright yellow stain, the 



14 REAGENTS AND MEDIA. 

nucleus becoming more distinct. It is also use- 
ful in developing stratification and striation. It 
destroys color, and also exerts a destructive 
action upon tissues; hence is of value in sepa- 
rating such firm structures as cuticle or epider- 
mis from the more delicate structures beneath. 

Iodine. — Dissolve one part of iodine and three 
parts iodide of potassium in five hundred parts 
of w^ater. This gives to starch a very distinctive 
blue color, while it stains protoplasm and some 
cell-w^alls yellow. For the latter purpose, a 
solution of double the strength is to be recom- 
mended. It causes a very slight contraction of 
the protoplasm, and makes nuclei more con- 
spicuous. The tincture, which is useful in cer- 
tain cases, is not of so general value, though it 
should be kept on hand. It causes a contraction 
of watery bodies, and would therefore be of no 
use for the examination of such structures in 
situ. 

Iodide of Zinc. — This is an important solu- 
tion for the development of the iodine reaction 
in resisting^ structures. The chloro-iodide is of 
equal value for the same purpose. 



REAGENTS AND MEDIA. I5 

Millon's Test. — The acid nitrate of mer- 
cury. A useful test for protein compounds, 
which it colors red. 

Calcium Chloride. — A solution of one part 
calcium chloride and two parts water, is use- 
ful in studying inuline. Because of its attrac- 
tion for water, it renders the latter insoluble, and 
it also serves as a valuable preservative medium 
when more highly diluted. 

Chloride of Iron. — A solution of one part 
chloride of iron to twenty parts of water is of 
some value in studying resins, to which it im- 
parts, a more or less well-defined odor. 

Fehling's Solution. — This is an important 
solution for the detection and recognition of 
grape sugar. The solution is made by dissolv- 
ing 34.64 gr. of crystallized, pure, copper sul- 
phate in a little distilled water. Dissolve 200 
gr. tartrate of potash and soda in 500 c. c. of 
caustic soda of sp. gr. 1.12 at 60° F. Gradu- 
ally add the first solution to this, and bring the 
w^hole to 1,000 c. c. Care must be taken to 
preserve this solution in tightly-stoppered bot- 
tles, that carbonic acid may not be dissolved by 



1 6 REAGENTS AND MEDIA. 

it. The reaction is accomplished by treating the 
specimen, and heating to the boiling point. The 
sugar causes a reduction of the copper oxide, 
which falls as a reddish precipitate. 

Schultze's Solution. — To a solution of 
potassium chlorate add nitric acid. By macera- 
tion with the aid of heat, it destroys intercellular 
substance, and the solution is therefore valuable 
for the separation of cells. 

Bleaching Solution. — Perhaps the best for 
the purpose is the French, a solution of chlori- 
nated soda. This is essential when it is desira- 
ble to stain sections, or w^hen we wish to get the 
cellular structure well cleared for examination. 
By its action all color and nitrogenous com- 
pounds are destroyed, and if the action be too 
long continued even the cellular structure it- 
self will be destroyed. A few minutes gener- 
ally suffice. The action may be hastened by 
placing the specimen in the sun, but in any case 
it should be carefully watched and the action 
arrested at the proper moment by washing with 
clean water. 

Strong acids should be kept in glass-stoppered 



REAGENTS AND MEDIA. 1 7 

bottles, and the required amount removed at the 
time of use, by means of a dipping tube, one for 
each reagent. Distilled water, dilute acids, etc., 
are most conveniently kept in wash-bottles, such 
as are in use in chemical laboratories. 



VEGETABLE PRODUCTS. 



Protoplasm. — The essential portion of every 
living cell. It is a colorless, semi-fluid sub- 
stance, and usually contains cavities or vacuoles, 
filled with cell sap. Through it are distributed 
the various granular contents of the cell. In 
water it is insoluble. Strong alcohol extracts 
the water, and causes the entire protoplasm to 
contract toward the centre of the cell with a dis- 
appearance of the vacuoles. Iodine produces a 
very characteristic yellow stain. Strong alkalies 
do not cause any particular change, but if di- 
luted, the protoplasm is readily dissolved. All 
acids cause a contraction, or coagulation, while 
nitric acid also imparts a bright yellow color to 
it, especially under the influence of gentle heat. 
Acid nitrate of mercury (Millon's test) produces 
a red color characteristic of albuminous com- 
pounds; calcium chloride causes contraction by 
dehydration; glycerine renders more transparent; 
bleaching solution causes a complete destruction. 



VEGETABLE PRODUCTS. I9 

Protoplasm is best examined in water. Cyclosis 
and vacuoles are to be observed best in large, 
thin-walled hairs, such as are found in the sta- 
mens of Tradescantia. 

Nucleus. — A modified form of protoplasm, 
the reactions for which are precisely the same. 
The form is usually round or oblong. When 
there are no vacuoles its position is quite central; 
but as vacuoles appear and enlarge, the nucleus 
takes a more lateral or terminal position in the 
cell. When inconspicuous they may be ren- 
dered more or less prominent by the use of 
alcohol, iodine, or acetic acid. Each nucleus 
contains one or more bright points, cavities, or 
solid bodies, called nucleoli. These are best 
seen in young cells of vigorous growth. 

Chlorophyll. — The green coloring matter of 
plants. A pigment distributed through special- 
ized albuminous bodies — the chlorophyll gran- 
ules, and dissolved therefrom by the action of 
alcohol or ether. The color is entirely destroyed 
by the action of nitric acid or of bleaching 
solution. Chlorophyll is generally found in a 
granular form, and these grains, as they are 



20 VEGETABLE PRODUCTS. 

called, are very variable in size. In Spirog-yra 
it takes the form of spiral bands, while in zoo- 
spores, etc., it appears uniformly distributed 
through the protoplasm. Chlorophyll is best 
examined in water. Its forms may be studied 
with advantage in Spirog-yra, mosses, the gemmae 
of liverwort, and in the cells of Vallisne^Ha 
spiralis. 

Chlorophyll Granules. — These are albu- 
minous bodies which yield precisely the same 
reactions as protoplasm. When the color is 
dissolved out, the granule appears as a colorless 
refractive body. In the larger grains starch may 
sometimes be found enclosed. 

Aleurone. — Rounded grains of variable size, 
colorless and refractive. They frequently con- 
tain globoids, crystalloids, or crystals. Aleurone 
is readily soluble in water, dilute alkali, and 
acids, but insoluble in alcohol, ether, and the 
fixed oils. In order to find the aleurone, there- 
fore, sections must be made with a dry razor, or 
with it dipped in oil. Its behavior with reagents 
is the same as protoplasm, with the exceptions 
just noted. It is, therefore, an albuminous sub- 



VEGETABLE PRODUCTS. 21 

Stance. Examinations should be conducted in 
oil, glycerine, or alcohol. To render the grain 
quite transparent that the contents may be dis- 
played, they should be examined in an alcoholic 
solution of corrosive sublimate. Though gen- 
erally colorless, the grains sometimes are blue, 
red, yellow, or green. Aleurone is to be 
found abundantly in seeds, especially in those 
containing oil, such as the almond, Brazil nut, 
castor-oil bean, etc. 

Crystalloids. — Crystalloids are to be recog- 
nized as colorless, refractive bodies, having more 
or less well defined angles. They are distin- 
guishable from true crystals in that they are 
organic in their nature and yield the reactions of 
protoplasm, and in water swell up and lose their 
originally sharp outlines — the angles becoming 
rounded, or, as in the protein grains of the po- 
tato, appear to break up into plates or layers. 
They are to be found in those structures where 
there is a large accumulation of reserve food 
material, so that seeds or the rind of potato may 
be reckoned upon as good places to find them. 
They may be examined in oil or glycerine, or in 



22 VEGETABLE PRODUCTS. 

alcohol. Iodine solution is also a good medium, 
as the yellow color it imparts aids in making 
them more distinct. When enclosed in aleurone 
grains they cannot be distinguished until the lat- 
ter has been dissolved by water, or rendered so 
transparent that the former may be seen through 
it. It will be found advantageous to use the 
glycerine diluted with water in different degrees. 
Starch. — This substance is to be found in 
the form of refractive grains which present great 
external variations as to form and size. It is a 
matter of some difficulty oftentimes to distin- 
guish starch from oil by external appearance 
alone, especially in the case of small grains. 
Large grains, like those from potatoes, generally 
show well-defined rings concentric with the nu- 
cleus near the small end, and these at once serve 
to distinguish them from oil or other bodies. In 
case of even slight doubt, a test with iodine 
should be made. This reagent causes the almost 
immediate appearance of a beautiful blue color 
— the iodide of starch. Sometimes, however, 
the reaction is not easily obtained, as with wheat 
starch, so that unless the blue color appears 



VEGETABLE PRODUCTS. 23 

within a short time a drop of sulphuric acid 
should be used to hasten the change. The ap- 
pearance of rings, already spoken of, is caused 
by the presence of variable quantities of water in 
different parts of the grain, so that there thus 
arise layers which are more or less dense and 
refractive, according to the amount of water 
they contain. Treatment with dehydrating 
agents, as alcohol, causes a disappearance of 
the rings. Under the influence of potash or 
soda, according to the strength used, the grains 
swell up to many times their original size, and 
finally dissolve. Acids — especially sulphuric — 
produce the same change. We are to note in 
this case, however, important chemical changes. 
Thus the first change, involving only a differ- 
ence in molecular construction, is from starch 
into dextrine. The continued action of the acid 
causes this com^pound to be converted into grape 
sugar, which may then be proved by application 
of the appropriate test. Cold water causes no 
change, but when hot the grains swell up and 
finally burst. There is no true solution, how- 
ever, and in this condition the iodide color is 



24 VEGETABLE PRODUCTS. 

developed as well as in the original grain. 
Starch is composed of two substances which, 
though chemically the same, present important 
points of difference, particularly with regard to 
their behavior under the influence of different 
solvents. These substances are known as starch 
granulose and starch cellulose. The granulose 
is soluble in saliva with the aid of gentle heat, 
pepsin, organic acids, dilute chromic acid, and 
in other mineral acids of such dilution that they 
do not cause the grains to swell. The cellulose 
is unaffected by this treatment, and may be 
proved by the proper tests. When thus sepa- 
rated it will be found that it is the granulose 
alone which gives the blue color with iodine. 
The very uniform color developed in the fresh 
grain is due to the uniformity with which the 
granulose is distributed through the cellulose. 
Starch is generally to be examined in water, 
glycerine, or oil. It is to be found in all tissues 
— those containing a large amount of oil ex- 
cepted — which contain reserve material, as pota- 
toes, seeds, tubers, bulbs, medullary rays, etc. 
Inuline. — In this we have a modified form of 



VEGETABLE PRODUCTS. 25 

starch, the chemical composition being just the 
same. It is highly soluble in water, being held 
in solution by the cell-sap, from which it may be 
precipitated by the use of alcohol or other de- 
hydrating agents. If the precipitation is rapid, 
the inuline falls as small, frothy granules, but 
when the action is slow, then it comes out as 
large crystalline spheres, or sphere-crystals, as 
they are called. By treatment with iodine these 
simply take the yellow color of the solution, 
which still further serves to distinguish them 
from true starch grains. Like starch, this is one 
form of reserve-material. It is to be found in 
the roots of Compositce^ also in Cam-panulacece^ 
Lobeliacece^ etc. 

Cellulose. — This substance, in the form of 
the cell-wall, constitutes the framework of nearly 
all plants. When comparatively pure it is color- 
less, but as found in old tissues, as wood, where 
it is impregnated with a large amount of mineral 
matter, it very frequently becomes colored red 
or brown. The purest forms are to be found 
in such structures as cotton and other cells 
where the wall has not become lignified. In 



26 VEGETABLE PRODUCTS. 

the early stages of growth, the cell-wall will 
often yield the iodine reaction, especially if 
soaked in tincture of iodine, allowed to dry, and 
then wetted with water. As the cell becomes 
older, however, and the cellulose more dense, 
the reaction is developed with difficulty or not 
at all. This is particularly true of lignilied cell- 
walls, which, unless subjected to special treat- 
ment, only take on a yellow, or brownish yellow 
color. In such cases it will be advisable to first 
employ sulphuric acid, caustic potash, iodide of 
zinc or chloro-iodide of zinc. The action of 
these reagents seems to be simply to open up the 
molecular structure to such a degree that the 
iodine can act. Sulphuric acid causes cellulose 
to swell up, and, if of sufficient strength, dis- 
solves it, with final conversion into glucose. 
Other mineral acids act in the same way, though 
not so quickly. Caustic alkalies cause a similar 
enlargement. Hence these reagents, either in 
the cold or hot, are of great use in developing 
stratification and striation of the cell-wall. The 
best solvent is the ammoniated copper oxide 
solution, since it acts quickly and does not pro- 



VEGETABLE PRODUCTS. 27 

duce any chemical change. The cellulose may 
be precipitated from such solution by the aid of 
acids. The different forms of cellulose will be 
found specially treated of in the tables. Paren- 
chj'ma will be best studied in pith, and funda- 
mental tissues in general; collenchyma in marine 
algae, stem of squash, and in most structures 
which swell up strongly when immersed in 
water; periderm, or cork, in the bark of the cork 
oak, bark of grape vines, and wherever the epi- 
dermis has been replaced; cuticle, on the exter- 
nal portion of epidermis; sclerenchyma, in pears, 
and in the joints of grasses, especially bamboo, 
and in the tissues of palm stems; lignine, in the 
cells of wood, particularly of several years' 
growth; bast, in the bark of flax, linden, elm, 
nettle, etc. 

Silica. — Appearing as a transparent deposit, 
it often presents very beautiful structural mark- 
ings. The best forms are to be found in the 
silicious valves of diatoms, the cuticle of Eqicise- 
tuiii^ and in the epidermal tissues of grasses. 

Dextrixe. — This will be found only after the 
action of acids upon starch, the chemical com- 



28 VEGETABLE PRODUCTS. 

position of which is identical. With iodine, 
there is no change. It turns the plane of polar- 
ization to the right, and with acids is converted 
into glucose. 

Grape Sugar. — Glucose. This sugar occurs 
naturally in grapes, and is a product of the action 
of acids upon starch, cellulose and dextrine. Its 
presence may be determined by the polariscope, 
or by the use of Fehling's copper solution. At 
a boiling heat the sugar is oxidized at the 
expense of the copper oxide, which be- 
comes reduced, and is precipitated as a red 
powder. 

Cane Sugar. — Sucrose. While this sugar 
occurs naturally, it cannot be produced arti- 
ficially. It contains one molecule of water less 
than glucose. Its presence is to be proved by 
first showing the absence of grape sugar. The 
specimen is then digested for a short time with 
hydrochloric or sulphuric acid, by which all 
cane sugar will be converted into grape sugar. 
The free acid is then to be neutralized by means 
of sodium carbonate, and the solution tested for 
grape sugar by means of Fehling's solution, as 



VEGETABLE PRODUCTS. 29 

before. It is to be found in the sugar-maple, 
sugar-cane, water-melon, beet, etc. 

Gums. — These compounds occur as the viscid 
secretions of plants, such as are to be found on 
cherry and peach trees. They present no struc- 
tural features. The few reactions they yield are 
sufficiently indicated in the tables. 

Wax. — A white or yellowish substance, 
sometimes crystalline, to be found as the bloom 
of grapes — the thin coating which renders many 
plants glaucous, and on the fruit of the bayberry, 
etc. 

Resins. — Substances largely developed in 
plants of the pine family. They are generally 
found in special channels, or resin passages. 



COURSE OF STUDY FOR A BEGINNER. 



1. — Protoplasm. 

Zoospores, vacuoles, cyclosis. 

2. — NiLcleiLS. 

Form and position in the cell. Nucleoli. 

3. — Chlo7vpJiylL 

Form and size of grains, pigment, granule, 
enclosures. 

4. — Aleitrofie. 

5. — Crystalloids. 

Different forms. 

6. — Starch. 

Form and size of grains, granulose and cellulose. 

7. — Imdi7ie. 

Development of the sphere-crystals. 

8. — Crystals. 

A. Calcium oxalate. 

Octohedra, hendyohedra. 

B. Calcium carbonate. 

Cystoliths, solubility in acids with effer- 
vescence. 

C. Calcium sulphate. 

Acicular crystals. (.?) 

9. — Globoids. 

Calcium and magnesium phosphate in aleurone 
grains. 



COURSE OF STUDY FOR A BEGINNER. 3 1 

10. — Cell-wall. 

Cellulose, stratification and striation, special 
modifications. 

TISSUES AND ORGANS. 

11. — Root. 

Root-cap, vascular elements, cambium, epi- 
dermis and root hairs. 
Periderm. 

12. — Stem. 

A. Medullary system. 

Pith, medullary rays. 

B. Wood system. 

Wood, medullary sheath, dotted, spiral and 
annular ducts, etc. 

C. Cambium. 

D. Cortical system. 

Liber. 

Parenchyma, bast, laticiferous vessels, 
intercellular spaces, resin passages. 
Mesophloeum. 

Arrangement of cells, intercellular spaces, 
etc. 
Epidermis. 

Cuticle, hairs. 
Corky or suberose layer, periderm, cork 

cambium or phellogen layer. 



32 COURSE OF STUDY FOR A BEGINNER. 

l^. — Leaf. 

A. Mesophyll. 

Intercellular spaces, laticiferous vessels, 
palisade cells. 

B. Epidermis. 

Cuticle, trichomes, stomata. 

14. — A comparison of the exogenous and endogenous 
stems. 

After thoroughly completing this course, the 
student may then with advantage take up special 
questions, such as the formation of tissues, the 
structure of different organs, and many other 
questions which may be suggested during the 
course as given, and which the student will often 
have a strong inclination to follow, without any 
regard to well-defined system, but in the end, 
if not before, he will find of great importance. 



34 



REAGENTS AND MEDIA. 



Table L Cell-Contents. 



NITROGENOUS SUBSTANCES. 



Reagents. 



Proto- 
plasm. 



Physical 
Characters 



Water . . . 

Alcohol . . 

Ether . . . 

Iodine . . 



Oil (fixed) 

Caustic Pot- 
ash, or Soda 



Acetic Acid 



Hydrochlo- 
ric Acid . . 



Sulphuric 
Acid . . 



Nitric Acid 

Acid Nitr'e 
of Mercury 

Bleaching 
Solution . . 



Trans- 
parent. 
Colorless. 



Contracts, 
Vacuoles 
disappear. 



Yellow 
stain. 



Nucleus. 



Transpar- 
ent. 
Colorless. 
Round or 
Oblong. 



Contracts. 
More dense. 



Deep yellow 
stain. 




IAleurone. 



Rounded 
Grains, 
I colored or 
I colorless. 
I Refractive. ! 
! i 

! 

Soluble. I 



Crystal- 
loids. 



Refractive. 

Well 

defined 

Angles. 

Enlarge. 
Angles 
become 

rounded. 

c 1 u: Contracts. 1 Contracts. Contracts. 

boluDie. I Insoluble. ' Insoluble. Insoluble. 



Soluble. 



Insoluble, j Insoluble. 



Y""?:L-„ ! Yellow. 



Yellow. 



All Albuminous Compounds are soluble in Alkali. 



Glycerine 



Calcium 
Chloride 



Coagulates. 
(Strong 
Acid.) 

Coagulates. 
(Strong 
Acid.) 

Coagulates. 

(Strong 

Acid.) 

Yellow. 
Coagulates, 
(Str'gAcid.) 

Red. 



More 

dense. 



More 

dense. 



More 

dense. 

Yellow. 
More 

dense. 



Soluble. 



Soluble. 



Color 
destroyed. 



Yellow. 
More 
dense. 

Red. 



Soluble in 
dilute Acid. 



Soluble in 
dilute Acid. 



Soluble in 
dilute Acid, 



Soluble in 
dilute Acid, 



Red. 



Partially 

Soluble 

in 

dilute 

Acids. 



Yellow. 
Red. 



All Nitrogenous substances are rapidly destroyed. 



Finally ren-i Finally 

ders more j more 
transparent. ; transparent. 

Contracts. I Contracts. 



Strong Glycerine ren- 
ders the grain more 
transparent. 



Contracts. Contracts 



Partly 
soluble. 



Contracts. 



* Starch granulose, which takes the blue color with iodine, is soluble in saliva at 50° 
C, and in weak solutions of chromic acid. Starch cellulose is not colored by iodine, and 
after removal of the granulose, may be dissolved in ammuuiated copper oxide. 



REAGENTS AND MEDIA. 



35 



Table I. (concluded). 



AMYLACEOUS. 



Refractive. 

Amorphous, 

or 

Crystalline 

Spheres. 



Soluble. 



Starch.* 



Refractive. 

Generally 

showing 

concentric 

Rings. 



MINERAL. 



Calcium ?-^.^„^jy.^ i Calcium 



Oxalate. 



Precipitated Rings dis- 
in Sphere- | appear by 
Crystals. Dehydrat'n, 



Blue, espe- 
cially after 
action of 

H2 SO4. 



Soluble. 



Soluble. 



Soluble. 



Soluble. 



Soluble. 



Sphere- 
Crystals. 
Insoluble. 

Insoluble. 
Sphere- 
Crystals. 



Swells 
strongly, 
and finally 
breaks up. 



Swells, and 

is converted 

into Grape 

Sugar. 

Grains 

swell. 

Soluble. 



Slowly 
soluble. 



Octohedra,6 
equiv.HsO. 

Hendvohe- 

dra, 2 equiv. 

H2O. 



Insoluble. 



Soluble. 



Soluble. 



Carbon- 
ate. 



Sulphate. 



Crystals in 

Cellulose 

Matrix. 

Cystoliths. 



Solublewith 
evolution 
of Gas. 

Solublewith 

evolution of 

Carbon 

Dioxide. 

Solublewith 
efferves- 
cence. 



Solublewith 
Soluble. effers-es- 



Crystals. 



Insoluble. 



Insoluble. 



Insoluble. 



Insoluble. 



Globoids, 

Ca. AND Mg. 

Phos. 



Non- 
crystalline, 
enclosed in 
Aleurone 
Grains. 



Soluble. 



Soluble. 



Soluble. 



Soluble. 



Oil. 



Refractive. 



Refractive 
Globules. 



Soluble. 



Soluble. 

Soluble 
with 
Heat. 



t Attention is called to this salt, not because of frequent occurrence, but that the stu- 
dent may further have an opportunity to prove that it is rarely if ever present. 



36 



REAGENTS AND MEDIA. 



Table II. Cellulose Forms. 



Physical Characteristics . . . . 



Water . 

Alcohol 
Iodine . 



Potash or Soda 



Acetic Acid . 
Sulphuric Acid 



Nitric Acid 



Bleaching- Solution 



Glycerine 

Ammoniated Copper Oxide 
Schultze's Solution . . . , 



CELLULOSE. 



Simple Forms. 



Parenchyma. 



Cells usually 

thin-walled. 

Colorless. 



Contracts. 

Blue after dry- 
ing and a2:ain 
wetting- in H2O. 



Periderm. 



Cells thin- 
walled, tabular, 
and arranged 
radially. 
Yello^v or 
brown. 



Yellow. 



LiGNIFIED 

Forms. 

Collenchyma. 

Walls locally 

thickened, 
usually at the 

angles. 

Absorbs water 

rapidly. 

Swells. 



Contracts. 
Yellow. 



By penetrating the cellular 



Caustic alkalies cause all cellulose 
by 



Causes Cellulose to swell up, more or less, and 



Destroys deli- 
cate tissues 
when hot. 

Destroyed by 
long action. 



Swells 
somewhat. 



Bleached. 



Destroyed. 



Destroyed 

by continued 

action. 



Cellulose soluble 



Useful for 



Iodine and Sulphuric Acid . . 

Iodine and Nitric Acid, or Iodide' 
of Zinc I 



Blue. 
Blue. 



Yellow brown. 
Blue. 



Blue. 
Blue. 



REAGENTS AND MEDIA. 



37 



Table II. {concluded). 



CELLULOSE. 



LiGNiFiED Forms. 



Cuticle. 



Dense layer 
on the external 
portion of epi- 

dei'mis. 
Often horny. 



Sclerenchyt 



Parenchyma 

cells strongly 

thickened, and 

showing many 

radial channels 

Tissue gritty. 



Yellow. 



Wood. 



Bast. 



SILICA. 



Cell wall i Long fusiform 

strongly thick- I cells, with thick' Transparent, 

ened. Colored :walls and small often crystalline, 

or colorless. ' central cavity, j Chiefly in 

Stratification \ Colorless. ! epidermal 

and striation. 1 Stratification tissues. 

Tissue dense. and striation. 



Stratification 

and striation 

disappear. 

Yellow. 



Stratification 

and striation 

disappear. 

Yellow. 



substance, oil renders the entire structure more transparent. 



structures to swell up. The original volume may be restored 
dehydrating agents. 



. . Causes cellular structure to become more transparent. 



by continued action dissolves it with the formation of Glucose. 



Swells. 

Separated from 

other tissue. 



Bleached. 



Swells. 



Bleached. 



Stratification 

and striation 

developed. 

Bleached. 



Stratification 

and striation 

developed. 

Bleached. 



Renders all structure more transparent. 



in fresh solution, from which it is re-precipitated by acids. 



separation of cells by destruction of the connective tissue. 



Yellow. 
Blue. 



Yellow. 
Blue. 



Yellow. 
Blue. 



Yellow. 
Blue. 



38 



REAGENTS AND MEDIA. 



Table III. Plant Products. 





PLANT PRODUCTS. 




Dextrine.* 


Sugars. 




Grape. 


Cane. 




Soluble. 


Soluble. 
Soluble. 

Reduces the 
Copper Oxide. 


Soluble. 


Alcohol 


Soluble. 


Ether 




Fehling's Solution 


.... 


Polarization of Light 


To the right. 


To the right. 


.... 




Yields Mucic 
Acid. 

No color un- 
less mixed 
with starch. 


Gives Oxalic 
Acid. 


Glucose. 










Sulphuric Acid •••••••.. 


Converts into 
Glucose. 


Cold Concen- 
trated Acid 

dissolves. 

No color. 


Yields 




Glucose. 


Caustic Potash, or Soda 


.... 


Decomposed. 
Brown. 


.... 


Chloride of Iron 




.... 


.... 



* Intermediate between Starch and Sugar, and to be found after the former has 
been acted upon by acids. 



REAGENTS AND MEDIA. 



39 



Table III. {concluded). 



PLANT PRODUCTS. 



Gums. 


Miscellaneous. 


Arahin. 


Bassorin. 


Cerasin. 


Wax. 


Resins. 


Soluble. 


Swells. 
Insoluble. 


Swells. 
Insoluble. 


Insoluble. 


Insoluble. 


.... 





.... 


Insoluble in 
the cold. 


Soluble. 


.... 


.... 


.... 


.... 


Soluble. 


.... 





.... 


.... 





.... 


.... 


.... 


.... 


.... 


Yields Sol- 
uble Salt. 


Mucic and 
Oxalic Acids. 





.... 





.... 





.... 


.... 


.... 


Yields Sol- 
uble Salt. 


Gives g-um and 
sugar. 





^ 





Insoluble. 


.... 


.... 


.... 


Soluble. 


.... 


.... 





.... 


Green or blue. 



BOOKS OF REFERENCE. 



The following books will be found useful as 
works of reference, either upon the special ques- 
tions mentioned in this work, or upon the use of 
the microscope and the mounting and preserva- 
tion of objects: — 

Allgemeine Botanik. Weiss. 

Beal on the Microscope. 

Carpenter on the Microscope. 

Frey on the Microscope and Microscopical Tech- 
nology. Cutter. 

Micrographic Dictionary. Griffiths and Henfrey. 

Preparation and Mounting of Microscopic Objects. 
Davies. 

Text-Book of Botany. Sachs. 

Text-Book of Botany. Bessey. 

The Microscope in Vegetable Physiology. Schacht. 



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